Valve for gas or air compressors



j i UNITED "STATEsfPATE-NT OFFICE.

SAMUEL W. JOHNSON, OF NEWPORT NEWS, VIRGINIA.

VALVE yFOR GAS on AIR colvlPFu-:ssousI SPECIFICATION formng part of Letters Patent No. 543,446, dated July 23, 1895.` Y

v.To all whom it may concern,.-

` Be it known that I, SAMUEL W. JOHNSON, a citizen of the United States, residing at New- A port News, in the'county of Warwick and State gas or air compressors; and it consists in the novel construction and arrangement ot' the various parts, as Vwill be hereinafter more fully described, and specifically pointed out in the claims.

The principalv objects of the invention are, Iirst, to provide valves of the class above men'- tioned, in which liability to breakage and consequent damage to the compressor shall beV reducedto a minimum; second, to yincrease `the guldlng-surfaces which hold the valves in acentral position; third, to prevent the rapid n wearing'of the valves, and, fourth, to lessen Y the pounding and thumping noise so common `compressor. Y .nary or any approved construction, the pisto valvesnow in use. These objects are attained by the mechanism illustrated in the accompanyingdrawings, in which- Y Figure 1 represents a vertical section of the upper part of the cylinder and piston of an `air or gas compressor provided with my improved valves and valve-guides.

Fig. 2 is a vertical section of the valves and valve-guides enlarged.- Figs. 3, 4, and 5 are transverse sectional views taken on. lines a: rc, 'y y, and z z,

respectively, of Fig. 1.

Referring to the drawings, the letters A A indicate, respectively, the cylinder and cylinder-head, and B the piston, of a. gas or air These parts may be of the orditon being provided with the usual rod b and gas or air inlet ports b.

`The letters C C indicate, respectively, the suctionand discharge valves. The suctionvalve Vis T-shapedand operates in a flanged guide 1, the ilange of which is screwed into the upper end of the piston and securely held in place by a screw 2, said screw being pre- Applioation tiled January 13, 1894. Serial No. 496,789. (No model.)

vented from turning by a p in 3. .The stem ofthe suction-valve is screw-threaded and provided with a screw-threaded nut 4, which is held against displacement` by a pin 5, said nut being provided on its innerface with an annular groove 6, in which isseated a stiff coil-spring 7, the purpose of which will be hereinafter explained. A similar spring 8, but of lighter construction, surrounds the valvestem between the nut-4 andthe end of the guide 1 and-serves to close the valve. The inner or under -faceof the valve-head is provided with an annular recess 9 surrounding the valve-stem, into whichv recess is received the top edge of `a projection 10 ot'z the valveguide 1. By this peculiar construction of the valve-guide and valve-head the valve is accurately guided in'itsworking. The valve-guidel is provided with Vports 11. Fig. 3.,) i

The discharge-valve C,.whcl 1is also T- shaped, operates in a guide 2, having wings 13, which serve to maintain said guide in proper place within the cylinder-head. The outer end ofthe guide and the cylinder-head cap are provided withan annulargroove 14 and 15, respectively, and a coil-spring 16 seated (Better shown in in said grooves'serves to hold said guide down.

The discharge-valve is seated in a steel seat 17, which-is screwed into the inner flange ofv the cylinder-head, as shown in Fig. 1, andthe inner or under face of its head is provided with an annular recess 18, surrounding the stem, to receive an annular projection 19 of the guide 12, which projection working in said recess serves to accurately guide the valve in its operations. The inner portion of the valve-stem is recessed to form an annular shoulder 20, and the bore of the valve-guide at its innerend is recessed toform an annular shoulder 21, between which shoulders surrounding the said'stemis a stift coil-spring 22, just long enough to permit it to act only when the valve is raised to nearly its full heights'` The outer portion of the stem is also x recessed to form a'shoulder 23, and the bore -of the valve-guide is recessed to form shoulder 24, and a light coil-spring 25,' surrounds IOS the stem betweensaid shoulders and serves to exert a constant pressure on the valve.

The letter D indicates the discharge-pipe, through which the compressed gas or air escapes. The operation of the suction-valve is as follows: When the piston commences the downward stroke the gas or air enters the piston through the ports band,passing through ports l1 of the valve-guide, strikes against the edge of the suction-valve, overcomes the weight of said valve and the force exerted by the light spring 8, and raises said valve from its seat until it is checked by the stiff spring '7 coming in contact with the lower end of the valveguide 4, thus preventing the sudden shock which would otherwise occur if it were not for theinterposed spring. Without the spring the stem soonv breaks oft just above the nut, and the valve being thus freed ofits retaining means will get on top of the piston and the cylinder-head is soon destroyed.

The operation of the discharge-valve will be readily'understood, and its action is similar to that of the suction-valve, and the special advantages derived from the novel construction and arrangement of the various parts that accrue to one apply to the other.

It is very necessary to the economical Working of a gas or air compressor that the gas or air should pass by the suction-valve with the least possible pressure. Consequently the spring 8, which causes the valve to close quickly when it is at the bottom of the stroke, is made very light and of a length that will not permit it to exert any pressure when the valve is closed, while the spring 7 is just long enough to allow the valve to open sufficiently before Ait begins to act.

The annular projections of the respective valve-guides, fitting and working snugly within the recess made in the inner or under faces ot' the respective valve-heads, serve to tighten the valves and lengthen the guiding-surface of the valve-stems, and at the same time provide a second guiding-surface on the outside of cach recess. Another advantage of this novel construction is that in opening the valve the gas or air can only strike directly on a part of the under surface of the valve, and consequently it is not opened with as much force as it otherwise would be, thus reducing the wear and noise caused bythe open ing and closing of the valve.

The valve-guide 1, having on its upper end the valve-seat, andprojection l0 being separated from the piston, is easily fitted up and when broken readily replaced. y

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent is` l. In a gas or air compressor, the combination with the tubular valve guide, of the suction valve having a stem working in said guide, and an ann ularly recessed head adapted to fit over and work upon the upper end of said guide, substantially as and for the purpose specified.

2. In a gas or air compressor, the combination with the suction valve, of the tubular valve guide, provided with vertical ports, the said valve having a stem working in said valve guide, and having a head recessed on its under side so as to fit over and work upon the upper end of the valve guide, substantially as specified.

3. In a gas or air compressor, the combination, with the suction valve, its tubular valve guide and recessed head fitting thereon, of

the nut at its lower end, the intervening springs, the discharge valve and its head recessed on the upper side and the springs arranged around the stem of the valve, the whole adapted to operate, substantially as specified. In testimony whereof I affix my signature in the presence of two witnesses.

SAMUEL WV. JOHNSON.

Vitnesses: CLARA L. JoHNsoN, ELLEN A. J oHNsoN. 

